This invention relates to an apparatus for analyzing a sample by irradiating the sample with the electron beam of an EPMA (electron probe micro. analyzer), etc., and detecting characteristic X-rays or the like emitted by the sample. More particularly, the invention relates to a sample.moving automatic analyzing apparatus of the type described in which the sample is moved to shift the position irradiated by the electron beam.
In a case where there are a plurality of areas at which a sample is to be analyzed by irradiation with an electron beam, the conventional practice is to set the positions of the analytical areas in advance and irradiate the sample with the electron beam based on this setting. In the process of ending the analysis of a certain analytical area and then moving the electron beam to the next analytical area, the electron beam is moved across the shortest distance, namely along a linear path, from the end point of one analyzed area to the starting point of the next area to be analyzed.
Though the surface of a sample has locations which are not suited to irradiation because they readily sustain damage owing to irradiation with the electron beam, the prior-art arrangements do not consider protecting these locations. As a consequence, a problem arises in which the sample is damaged or the apparatus is caused to malfunction as a result of electron.beam irradiation in the process of moving the electron beam. A measure to deal with this problem would be to shield the sample from the electron beam during movement. However, when the electron beam is shielded, it takes time for the electron beam to re.stabilize at the designated acceleration voltage and state of convergence, and another problem that arises is a decline in reproducibility. Still another problem is that a large error is produced when attempting highly precise analysis.
In the specification of Japanese Patent Application Laid-Open No. 1-143129, the application for which was filed by the present applicant, and which has been laid open in Japan, there is disclosed an apparatus in which, when there are a plurality of areas at which a sample is to be analyzed by irradiation with an electron beam, analytical conditions and analytical positions on a sample in a plurality of mappings are set by an operator and an analytical schedule is entered. Whenever a mapping ends, a mapping-end signal is transmitted, the next analytical condition and analytical position are set, and a mapping.start signal is transmitted. However, in the disclosed apparatus, no consideration is given to movement of the electron beam between analytical positions, and there is the possibility that the sample will be damaged owing to irradiation with the electron beam during such movement. Further, in the specification of Japanese Patent Application Laid-Open No. 63-318054, the application for which was filed by the present applicant, and which has been laid open in Japan, there is disclosed art in which a path along which the electron beam is scanned is designated by an input unit such as a mouse or tracking ball. However, the above.mentioned problems still arise since no consideration is given to movement of the electron beam other than movement along the scanning path.